So far, Microsoft has failed to convince many people that its Surface can replace both their PC and their iPad. Will that change with the new Surface Pro 3?

For the uninitiated, the Surface Pro is a full-fledged PC masquerading as a tablet. Call it a laplet. Or maybe a tabtop? The Surface has several unique features, such as a kickstand, a pen, a gorgeous touchscreen and a super-thin keyboard that doubles as a cover.

The Surface Pro 3, which goes on sale Wednesday for $800, improves upon all of those things that make it special.

Better kickstand and pen

The kickstand now leans just about all the way back, allowing you to write on the screen comfortably or tilt it back to the perfect position when it's on your lap. It's uncomfortable to rest the Surface on your lap while using the keyboard, though -- unless you like a thin, pointy piece of metal digging into your thighs.

The adjustable kickstand does cut down on the ouch-factor from previous Surface versions, but it still wobbles much more than a standard notebook PC would.

The pen is metal -- an upgrade from the junky plastic one Microsoft used to include. It has a button on the top that launches OneNote, and it even comes with a handy fabric holster on the keyboard so it won't get lost. The Surface renders handwriting very realistically, making broader strokes when you bear down on the screen.

The screen and keyboard are improved too ...

The touchscreen is remarkably sharp -- although not quite the Retina quality of Apple's(AAPL) iPad, but close. And at 12 inches, the screen is plenty large, though it features a somewhat odd 3:2 aspect ratio -- which is between an old-school television screen and an HD display. That means HD videos will have black bars on the top and bottom -- but not as much as on the iPad.

The older Surfaces had a 10.6-inch screen with a 16:9 aspect ratio. That was perfect for HD video, but made for cramped quarters when running apps -- and a really strange experience when flipping the tablet vertically to read ebooks.

Microsoft wants this to be your next PC

The Surface Pro 3's taller screen is a good compromise. It gives the device more real estate for apps. The black bars when watching video aren't all that noticeable. And flipping it vertically doesn't feel strange.

The Surface's keyboard is also improved. Though it's wafer-thin, typing on Microsoft's "type-pad" with mechanical keys is virtually indistinguishable from typing on a laptop keyboard. The trackpad, which was the single worst part of prior Surfaces, is vastly improved.

Mind you, any usable trackpad would have been an improvement over earlier versions, but the mouse on the Surface Pro 3 is actually plenty large and generally excellent.